1. Field of the Invention
One disclosed aspect of the embodiments relates to an imaging apparatus including a pixel circuit unit and a peripheral circuit unit on a single semiconductor substrate.
2. Description of the Related Art
For improved performance, in an imaging apparatus which includes a pixel circuit unit and a peripheral circuit unit on a single semiconductor substrate, providing an analog signal processing circuit or a digital signal processing unit (e.g., logic circuit) in the peripheral circuit unit has been considered.
Japanese Patent Laid-Open No. 2007-27711 discloses thicker gate insulating films of a sensor region and an analog region than a gate insulating film of a digital region.
Japanese Patent Laid-Open No. 2011-54832 discloses that the film thickness of insulating films of transistors is different between a light reception unit and a peripheral circuit unit.
For improved image quality, a pixel circuit unit needs to be driven at voltage as high as possible. On the other hand, power consumption of imaging apparatuses with increased functionality of a peripheral circuit unit therein has been a problem. According to Japanese Patent Laid-Open No. 2011-54832, a light reception unit and a peripheral circuit unit are driven at an equal voltage. It means that reduction of power consumption may not be sufficiently considered. The present disclosure provides an imaging apparatus which attempts higher image quality and lower power consumption.